Wireless mobile communication technology uses various standards and protocols to transmit data between a node (e.g., a transmission station or a transceiver node) and a wireless device (e.g., a mobile device). Some wireless devices communicate using orthogonal frequency-division multiple access (OFDMA) in a downlink (DL) transmission and single carrier frequency division multiple access (SC-FDMA) in an uplink (UL) transmission. Standards and protocols that use orthogonal frequency-division multiplexing (OFDM) for signal transmission include the third generation partnership project (3GPP) long term evolution (LTE), the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard (e.g., 802.16e, 802.16m), which is commonly known to industry groups as WiMAX (Worldwide interoperability for Microwave Access), the IEEE 802.11 standard, which is commonly known to industry groups as WiFi, or Wireless Gigabit (WiGig) Alliance. WiGig is a trade association that develops and promotes the adoption of multi-gigabit speed wireless communications technology operating over an unlicensed 60 GHz frequency band. WiGig alliance was subsumed by the WiFi Alliance and promotes the IEEE 802.11 ad protocol.
In 3GPP radio access network (RAN) LTE systems, the node can be a combination of Evolved Universal Terrestrial Radio Access Network (E-UTRAN) Node Bs (also commonly denoted as evolved Node Bs, enhanced Node Bs, eNodeBs, or eNBs) and Radio Network Controllers (RNCs), which communicate with the wireless device, known as a user equipment (UE). The downlink (DL) transmission can be a communication from the node (e.g., eNodeB) to the wireless device (e.g., UE), and the uplink (UL) transmission can be a communication from the wireless device to the node.
The eNB can have multiple antennas used for transmission to the UEs, allowing the eNB to use multiple-input and multiple-output (MIMO). MIMO is a smart antenna technology that refers to the use of multiple antennas at both the transmitter and receiver to improve communication performance, where input and output refer to a radio channel carrying the signal, not necessarily to the devices having antennas. In the existing LTE specification (e.g., 3GPP LTE technical specifications (TS) Release 10), up to eight transmit or receive antennas can be used, or up to eight channels can be used for transmission of a resource.
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.